Correction to This Article
A Dec. 18 Page One article on the climate talks in Copenhagen incorrectly said that the Bush administration did not ratify the Kyoto Protocol. The Bush administration did not submit the treaty to the Senate for ratification.

COPENHAGEN -- With an offer of significant new aid to help poor nations cope with the effects of global warming, the Obama administration began a major diplomatic effort Thursday aimed at saving the troubled climate talks before the president's expected arrival Friday morning.

The United States is pressuring developing countries to agree to emissions cuts along with the industrialized world for the first time, and insisting on transparent monitoring of those reductions. High-ranking U.S. officials were assuring nations behind the scenes that after years of resistance, Washington is also serious about reducing emissions at home and doing more to prevent global warming.

Concerned that the process had broken down so badly that world leaders would not have a document to consider Friday, Secretary of State Hillary Rodham Clinton pushed to establish a small, representative group of nations that could work through the night to produce a text that President Obama and others could use as a basis for final negotiations.

In a private meeting, Clinton told Brazilian officials that a climate change bill that was passed by the House would set aside billions to help preserve tropical rain forests in developing countries. U.S. negotiators also labored to distinguish themselves from George W. Bush's administration, which did not ratify the Kyoto Protocol. In fact, U.S. officials added, the new administration is taking steps with or without Congress to reduce carbon emissions through new fuel standards and other measures. "They are saying, 'Trust us that we can do better,' " said Brazil's climate change ambassador, Sergio Serra, who attended the meeting with Clinton on Thursday.

Though the talks remain fragile, the U.S. moves appeared to rebuild momentum after comments by major participants, most notably China, that chances of even a modest deal were fading. The shift happens as the United States backed what amounts to the single biggest transfer of wealth from rich to poor nations for any one cause -- in a sense offering compensation for decades of warming the Earth.

Clinton pledged that the country would help mobilize $100 billion a year in public and private financing by 2020 -- an amount that is almost equal to the total value of all developmental aid and concessional loans granted to poor nations by the United States, Europe and other donors this year. She did not specify how much the U.S. government would commit to giving, but a senior administration official said it would be 20 to 30 percent. Administration officials said they envisioned most of the money coming from private sources, or from revenue generated by a cap-and-trade scheme, but other sources could include redirecting existing subsidies or a tax on bunker fuel.

'Running out of time'

Any new assistance -- as well as Obama's signature on an agreement here, Clinton said -- would depend on "transparency" and "monitoring" of emissions cuts. Clinton said the historic talks must result in an international accord that includes reduction commitments from developed and major developing countries; financial and technological assistance for poor nations; and a way to independently verify the cuts all countries make. Such language is essential to U.S. senators, who have yet to pass climate legislation and would vote on ratification of any climate treaty.

Clinton specifically warned that China -- which has resisted attempts for international verification of emissions cuts and told officials here before Clinton spoke that a global pact seems unlikely -- must agree to monitoring if a deal is to be reached.

"We're running out of time," Clinton said at a news conference. "Without the accord, the opportunity to mobilize significant resources to assist developing countries with mitigation and adaptation will be lost."

The ultimatum appeared to sway many of the small island states, which are vulnerable to sea-level rise and have been demanding a legal treaty that would aim to prevent the average global temperature from rising higher than 2.7 degrees Fahrenheit above preindustrial levels. In a meeting between Clinton and representatives from 30 island nations, according to a participant, delegates said they would accept a higher temperature threshold of 3.6 degrees but expected the United States to offer more money for adaptation in the short term. Clinton said that would happen.

Yet most analysts have diminished expectations for the document that leaders may ultimately sign Friday. Rather than a formal new treaty, most are expecting a political agreement that would form the basis for a broader, more detailed accord perhaps by mid-2010.

The current emissions cuts that would be incorporated as part of any future pact have come under fire as too weak to curb dangerous global warming. An internal U.N. analysis that surfaced Thursday afternoon predicted that even under the most ambitious targets countries have pledged, future global temperature rise is likely to exceed 5.4 degrees Fahrenheit.